1. Field of the Invention
The present invention relates generally to tube bending equipment. More specifically, the present invention relates to mandrels used during tube bending operations. In particular, the present invention is directed to a cleaning attachment for cleaning the interior surface of a tube during a bending operation.
2. The Prior Art
An internal tube mandrel is commonly used to internally support a tube and prevent the tube from collapsing, deforming, crinkling, or binding during a bending operation. Typically, a tube mandrel is inserted into a tube prior to bending, an oil or other suitable lubricant is applied to the interior of the tube, and the tube is advanced over the tube mandrel during the bending operation. Although prior art tube mandrels may adequately prevent tube deformation during the bending process, the lubricant used during the bending process may pose several problems. For example, conventional tube mandrels do not retain the lubricating oil within the tube. As such, when a conventional tube mandrel is used during a tube bending process, the lubricating oil may not be confined to the area where it is needed, i.e., the bending area of the tube. In addition, the oil may also flow past the tube mandrel and out of the tube itself. This loss of oil is wasteful and may cause clean-up problems.
Following a tube bending process that utilizes a conventional tube mandrel, an amount of lubricating oil is inherently left behind within the tube. If the bent tube will be subjected to further manufacturing operations, then the excess oil may be undesirable. For example, if the tube will be subsequently welded or heat treated, then the oil may burn and produce unwanted smoke or fumes. In addition, the remaining oil may flow out of the tube during subsequent handling and create a hazardous and dirty work environment. Thus, the excess oil is usually removed from the tube before further processing.
The removal of the excess oil necessarily requires an additional step that adds to the manufacturing cost and processing time of the finished product. In a typical manufacturing scenario, the excess oil is either washed away or swabbed out of the tube. Following either cleaning process, the excess oil may be lost and nonrecyclable for all practical purposes. In addition, the oil removing process may itself create waste products that must be disposed of or treated.